Also started teaching it about toxcore's alloc/dealloc functions in
hopes of it catching some errors (it doesn't seem to be very good at
this, but maybe better than nothing?).
We now depend on libsodium unconditionally. Future work will require
functions from libsodium, and nobody we're aware of uses the nacl build
for anything other than making sure it still works on CI.
atoi doesn't check if the conversion from string to int succeeded
which doesn't allow us to do proper error handling.
We also now make sure that the port argument is a valid port
in addition to being properly converted
